Study of thermodynamical properties of liquid binary alloys by a pseudopotential method

On the bases of the Percus-Yevick (PY) hard sphere model as a reference system and the Gibbs–Bogoliubov (GB) inequality, a thermodynamic perturbation method has been applied with use of well known model potential. By applying a variational method the best hard core diameters have been found which correspond to minimum free energy. With this procedure the thermodynamical properties such as internal energy, entropy, Helmholtz free energy, entropy of mixing and heat of mixing have been computed for liquid NaK binary systems. The influence of local field correction function viz; Hartree (HR), Taylor (TY), Ichimaru-Utsumi (IU), Farid et al. (FD) and Sarkar et al. (SS) is also investigated. The computed excess entropy compares favourably in the case of liquid alloys while the agreement with the experiment is poor in the case of heats of mixing. This may be due to the sensitivity of the heats of mixing, with the potential parameters and the dielectric function.